Ability to turn on/off MCP servers per mode

[Juice10]

Description

Proposed solution here could be used to toggle MCP servers for each mode: #1104

Source: chat in live workshop: https://www.youtube.com/live/Nte0TxT9U20 aprox 1:30:00

[Triquetra]

Maybe on the tool use request, a button could be added to "disable MCP for Mode" to disable an MCP for the mode, and for more fine-grained control, maybe a "disable tool for Mode" to disable particular tools, but not the whole MCP.

The ability to set this pro-actively via settings or config file would be great, but the UI fallback - "Oh, I forgot I don't want to use that with this Mode..."

Inspired by this: RooCodeInc/Roo-Code#5322